Abstract: A stern torpedo defense system uses a pair of passive sonar towed tactical etectors in tandem alignment to detect the presence and trajectory of a stern torpedo attack. The detectors are towed below the wake of a surface ship and include arcuate arrays of transducer elements mounted in low self-noise, roll pitch and yaw stabilized platforms. The region aft of the stern of the ship is examined by an overlapping plurality of preformed passive sonar beams of preselected beamwidth. Signal processing means monitor the power level of the beams and detect the presence and trajectory of an attacking torpedo so that suitable ordinance may timely and effectively be deployed to destroy the torpedo and thereby thwart the attack.

Abstract: Two electrodes attached to the hull of a ship, one electrically connected ereto and one insulated therefrom, are employed to transmit, via sea water, an electrical signal. The current return of the signal passing through the ship's hull generates a magnetic field corresponding to the electrical signal. The magnetic field is effective to cause detonation of magnetically triggered naval ordnance at a range greater than the optimum range at which the ordinance would detonate in the absence of said generated magnetic field.

Abstract: An upper and a lower blade are fixed together at an adjustable angle and have means for mounting same on the leading edge of the propeller drive housing of an inboard/outboard motor to cut kelp and other seaweed which would otherwise foul the prop and clog the cool, sea water input vents. The cutter has adjustable brackets which will accommodate a wide variety of different types of propeller drive housings, and will accommodate outboard motors as well as inboard motors, and will even fit on the advance edge a sailboat keel. In one embodiment, it has a combination brace/mesh screen which extends from the cutter to the propeller drive housing in front of the cooling water inlets to keep bits of seaweed and other debris from entering and clogging the cooling system, causing overheating the destruction of the motor.

Abstract: 11. In a torpedo guard, a cable, a series of explosive units strung on the able, and individual proximity fuses positioned on said cable for each of said explosive units, the proximity fuse for any given explosive unit being adapted to fire said given unit upon the approach of a torpedo within a predetermined distance from said given unit.

Abstract: 1. In a torpedo detecting device of the class disclosed, the combination of n elongated hose-like member having a towing device secured to one end thereof whereby the member is adapted to be towed through a body of water, and means in said member and remote from said towing device for disconnecting said member at a predetermined point in closely spaced adjacency from the towing device comprising a helical coil of explosive fuse cord disposed only at said point and capable of sufficient explosive damage to sever the member substantially at said point, and a pair of electroresponsive detonators for firing said fuse cord, said detonators being disposed respectively in abutting relation to the ends of said cord.